Measurement systems for measuring blood pressure of a patient's body are well known in clinical appliances. They usually comprise a rinsing fluid reservoir which is connected using a fluid flow tube to a catheter tube, which in use penetrates a patient's body such that the rinsing fluid is supplied as a continuous rinsing fluid stream. Along the rinsing channel one or more valves can be arranged to manually stop the rinsing of the fluid into the patient's body.
The continuous measurement of a blood pressure of a patient is important to monitor the condition of ill patients. It is common that the measurement of the blood pressure is carried out using a single use pressure sensor and a rinsing system both mounted on an organizer plate. This organizer plate with the sensors is well accessible on heart level for the operator. The pressure sensor on this organizer plate is then connected to the patient via a long tube which is filled with liquid. Thus, the pressure signal is hydraulically transmitted via the transfer tube. Typically there is a 3 way stop cock between patient and pressure sensor for drawing blood samples Or injecting fluids.
The disadvantage of this system is that the pressure signal is falsified by the transfer characteristic of the long transfer tube system due to damping or resonance as a result of the length of the transfer tube.
As another possibility for measuring the blood pressure the use of a tip manometer is known. The tip manometer is located at the tip of the catheter tube such that in use the manometer is located inside the patient's body. Although such an arrangement provides a very good signal transmission it is very expensive and a larger diameter of the catheter tube is needed. Furthermore, controlling and adjusting the zero point pressure of the tip manometer is no longer possible after the catheter tube is placed inside the patient's body.